Hyaluronic acid-collagen matrices for dermal filling and volumizing applications

ABSTRACT

Hydrogels comprising a macromolecular matrix and water may be used for aesthetic fillers, for example, dermal fillers. The macromolecular matrix may include a crosslinked combination of hyaluronic acid and collagen.

This application is a continuation of U.S. patent application Ser. No.14/962,897 filed Dec. 8, 2015, which is a divisional of U.S. patentapplication Ser. No. 13/667,581 filed on Nov. 2, 2012, now abandoned,which claims priority to U.S. Provisional Patent Application No.61/555,970, filed Nov. 4, 2011, and also, which is acontinuation-in-part of U.S. patent application Ser. No. 13/605,565,filed on Sep. 6, 2012, now abandoned, which claims priority to U.S.Provisional Patent Application No. 61/531,533, filed on Sep. 6, 2011,and which is a continuation-in-part of U.S. patent application Ser. No.13/603,213, filed Sep. 4, 2012, now abandoned, which claims priority toU.S. Provisional Patent Application No. 61/531,533, filed Sep. 6, 2011,the entire disclosure of each of these applications being incorporatedherein by this specific reference.

This application generally relates to biocompatible, implantablecompositions and more specifically relates to hyaluronic acid-collagenbased compositions useful as dermal fillers.

SUMMARY

The present invention generally relates to a soft tissue aestheticproduct. In one aspect, the product comprises a filler comprising ahydrogel having a form suitable for injecting into human tissue; and alabel comprising instructions to inject the filler into the humantissue; wherein the hydrogel comprises water, and a crosslinkedmacromolecular matrix described herein.

Some embodiments include a method of improving an aesthetic quality ofsoft tissue of a human being comprising: injecting a hydrogelcomposition into a soft tissue of the human being to thereby improve theaesthetic quality of the soft tissue; wherein the hydrogel compositioncomprises water, and a crosslinked macromolecular matrix describedherein.

Some embodiments include a method of generating tissue comprisingcontacting a tissue with a hydrogel composition to generate anadditional amount of the tissue, wherein the hydrogel compositioncomprises water and a crosslinked macromolecular matrix describedherein.

Some crosslinked molecular matrices may comprise a hyaluronic acidcomponent; and a collagen component; wherein the hyaluronic acidcomponent is crosslinked to the collagen component by a crosslinkingcomponent; and wherein the crosslinking component comprises a pluralityof crosslink units, wherein at least a portion of the crosslink unitscomprise an ester bond or an amide bond.

BRIEF DESCRIPTION OF THE DRAWINGS

Some aspects of the present disclosure may be more clearly understoodwith reference to the appended drawings of which:

FIG. 1A is a plot of frequency sweep and FIG. 1B is a plot of strainsweep for a hydrogel in accordance with this disclosure.

FIG. 2 is an extrusion profile through a 30G needle for a hydrogel fromExample 4.

FIGS. 3A-3C shows respectively, micrographs (at 5× magnification) of (A)tissue adjacent to an implanted control composition of commercialcrosslinked hyaluronic acid gel, (B) tissue adjacent to an implantedcomposition of Example 3, and (C) tissue adjacent to an implantedcomposition from Example 4.

DETAILED DESCRIPTION

Some embodiments include a method of improving an aesthetic quality ofsoft tissue of a human. Such a method may comprise injecting a hydrogelcomposition, or a composition comprising a hydrogel, into a soft tissueof the human being to thereby improve the aesthetic quality of the softtissue.

Some embodiments may include a soft tissue aesthetic product comprising:a filler comprising a hydrogel having a form suitable for injecting intohuman tissue and a label comprising instructions to inject the fillerinto the human tissue.

A filler comprising a hydrogel or a hydrogel composition may be any kindof filler that is suitable for injecting into human tissue to improve anaesthetic quality of a soft tissue, such as a dermal filler, a breastaugmentation or reconstruction filler, a lip filler, hand rejuvenation,or the like. When injected, a hydrogel may stimulate tissue in-growthand generation after being injected into the soft tissue. In someembodiments, a hydrogel may stimulate collagenesis after being injectedinto the soft tissue.

Injecting a hydrogel comprising a crosslinked macromolecular matrixcomprising a hyaluronic acid component that is crosslinked to a collagencomponent may provide improved aesthetic quality for an extendedduration, as compared to injecting an identical hydrogel except thathyaluronic acid component and the collagen component are notcrosslinked.

Some embodiments include a method of generating tissue comprisingcontacting a tissue with a hydrogel composition to generate anadditional amount of the tissue. This method may be used to generatetissue both ex vivo and in vivo. In some embodiments, contact between atissue and a hydrogel may be ex vivo. In some embodiments, contactbetween a tissue and a hydrogel may be in vivo. Tissue types that may begenerated include, but are not limited to, adipose tissue, muscletissue, tendon tissue, cardiovascular tissue, neural tissue, bonetissue, and the like.

Some embodiments include a packaged product comprising a syringe loadedwith a hydrogel and a needle. A syringe may be fitted with a needle ofany size that is appropriate for injecting the hydrogel into the softtissue of interest, such as a needle with about a #25, about a #30, or alarger gauge.

A filler comprising a hydrogel may be suitable for injection if it canbe injected into the soft tissue of interest without unreasonabledifficulty, and includes fillers that can be dispensed from cannulashaving gauge as low as about #30 or about #25 under normal manualpressure with a smooth extrusion plateau.

Injection of a hydrogel may provide a soft tissue augmentation thatmimics the natural components of the skin. A hydrogel may be injectedintradermally or subcutaneously to augment soft tissue and to repair orcorrect congenital anomalies, acquired defects, or cosmetic defects.Examples of such conditions include congenital anomalies such ashemifacial microsomia, malar and zygomatic hypoplasia, unilateralmammary hypoplasia, pectus excavatum, pectoralis agenesis (Poland'sanomaly), and velopharyngeal incompetence secondary to cleft palaterepair or submucous cleft palate (as a retropharyngeal implant);acquired defects (post traumatic, post surgical, or post infectious)such as depressed scars, subcutaneous atrophy (e.g., secondary todiscoid lupus erythematosus), keratotic lesions, enophthalmos in theenucleated eye (also superior sulcus syndrome), acne pitting of theface, linear scleroderma with subcutaneous atrophy, saddle-nosedeformity, Romberg's disease, and unilateral vocal cord paralysis; andcosmetic defects such as glabellar frown lines; deep nasolabial creases,circum-oral geographical wrinkles, sunken cheeks, and mammaryhypoplasia.

Crosslinked hyaluronic acid, collagen, and crosslinked collagen, such asthose used in dermal fillers, do not promote cellular infiltration andtissue in-growth. Similarly, collagen simply blended into hyaluronicacid hydrogels does not promote tissue integration or de novo tissuegeneration. However, some hydrogels described herein do promote cellularmigration into the hydrogels and tissue formation within the gels whenimplanted in vivo.

A hydrogel may comprise water and a crosslinked macromolecular matrix.Typically, a crosslinked molecular matrix may comprise a hyaluronic acidcomponent and a collagen component, wherein the hyaluronic acidcomponent is crosslinked to the collagen component by a crosslinkingcomponent. A crosslinking component may comprise a plurality ofcrosslink units, wherein at least a portion of the crosslink unitscomprise an ester bond or an amide bond.

A crosslinked macromolecular matrix for a hydrogel may be synthesized bycoupling a hyaluronic acid with a collagen using a coupling agent, suchas a carbodiimide. In these hydrogels, hyaluronic acid may serve as abiocompatible water-binding component, providing bulk and isovolumetricdegradation. Additionally, collagen may impart cell adhesion andsignaling domains to promote cell attachment, migration, and other cellfunctions such as extra-cellular matrix deposition. The biopolymers formhomogeneous hydrogels with tunable composition, swelling, and mechanicalproperties. Compositions can be made to be injectable for minimallyinvasive implantation through syringe and needle.

Hyaluronic acid is a non-sulfated glycosaminoglycan that enhances waterretention and resists hydrostatic stresses. It is non-immunogenic andcan be chemically modified in numerous fashions. Hyaluronic acid may beanionic at pH ranges around or above the pKa of its carboxylic acidgroups.

Collagen is a protein that forms fibrils and sheets that bear tensileloads. Collagen also has specific integrin-binding sites for celladhesion and is known to promote cell attachment, migration, andproliferation. Collagen may be positively charged because of its highcontent of basic amino acid residues such as arginine, lysine, andhydroxylysine.

Because hyaluronic acid may be anionic and collagen may be cationic, thetwo macromolecules may form polyionic complexes in aqueous solution. Apolyionic complex may be significantly less soluble in water than eitherhyaluronic acid or collagen, and thus may precipitate out of aqueoussolution when the two macromolecules are together in a mixture.

Under certain conditions, a hyaluronic acid and a collagen may becombined in an aqueous liquid in which both components are soluble. Ahyaluronic acid and a collagen may then be crosslinked while both aredissolved in an aqueous solution to form a hydrogel. Reaction conditionssuch as the concentration of hyaluronic acid, the concentration ofcollagen, the pH of the solution, and salt concentration may be adjustedto help to prevent polyionic complex formation between anionichyaluronic acid and cationic collagen. They may also help to preventcollagen microfibril formation.

Some embodiments include a method of crosslinking hyaluronic acid andcollagen. This method generally comprises a dissolution step whichresults in an aqueous pre-reaction solution. In a dissolution step,hyaluronic acid and collagen are dissolved in an aqueous solution thathas a low pH and/or a salt to form an aqueous pre-reaction solution.

A hyaluronic acid-collagen crosslinking method further comprises anactivation step. In an activation step, an aqueous pre-reaction solutionis modified at least by adding a water soluble coupling agent and/or byincreasing the pH of the solution. If needed, a salt may also be addedto keep the hyaluronic acid and collagen in solution at the higher pH.Thus, a crosslinking reaction mixture comprises hyaluronic acid andcollagen dissolved or dispersed in an aqueous medium, a water solublecoupling agent, and a salt, and has a higher pH than the aqueouspre-reaction solution from which it was derived. The crosslinkingreaction mixture is allowed to react to thereby crosslink the hyaluronicacid and the collagen.

In some embodiments, the pH of the aqueous pre-reaction solution may beincreased and a substantial amount of fiber formation may be allowed tooccur in the solution before adding the water soluble coupling agent. Insome embodiments, the water soluble coupling agent may be added to theaqueous pre-reaction solution before substantially any fiber formationoccurs.

A crosslinking reaction mixture can react to form a crosslinkedmacromolecular matrix. Since reaction occurs in an aqueous solution, acrosslinked macromolecular matrix may be dispersed in an aqueous liquidin hydrogel form as it is formed by a crosslinking reaction. Acrosslinked macromolecular matrix may be kept in hydrogel form because,in many instances, a crosslinked macromolecular matrix may be used inhydrogel form.

In some embodiments, an aqueous pre-reaction solution or a crosslinkingreaction mixture may further comprise about 10% to about 90% of anorganic solvent in which hyaluronic acid has poor solubility, such asethanol, methanol, isopropanol, or the like.

After a crosslinking reaction has occurred, the crosslinkedmacromolecular matrix may be particulated or homogenized through a mesh.This may help to form an injectable slurry or hydrogel. A mesh used forparticulating a crosslinked macromolecular matrix may have any suitablepore size depending upon the size of particles desired. In someembodiments, the mesh may have a pore size of about 10 microns to about100 microns, about 50 microns to about 70 microns, or about 60 microns.

A hydrogel comprising a crosslinked molecular matrix may be treated bydialysis for sterilization or other purposes. Dialysis may be carriedout by placing a semipermeable membrane between the hydrogel and anotherliquid so as to allow the hydrogel and the liquid to exchange moleculesor salts that can pass between the membrane.

A dialysis membrane may have a molecular weight cutoff that may vary.For example, the cutoff may be about 5,000 daltons to about 100,0000daltons, about 10,000 daltons to about 30,000 daltons, or about 20,000daltons.

The dialysis may be carried out against a buffer solution, or the liquidon the other side of the membrane from the hydrogel may be a buffersolution. In some embodiments, the buffer solution may be a sterilephosphate buffer solution that may comprise phosphate buffer, potassiumchloride, and/or sodium chloride. A sterile phosphate buffer solutionmay be substantially isosmotic with respect to human physiologicalfluid. Thus, when dialysis is complete, the liquid component of ahydrogel may be substantially isosmotic with respect to humanphysiological fluid.

In some embodiments, a crosslinked macromolecular complex may furthercomprise an aqueous liquid. For example, the crosslinked macromolecularcomplex may absorb the aqueous liquid so that a hydrogel is formed. Anaqueous liquid may comprise water with a salt dissolved in it, such as aphosphate buffer, sodium chloride, potassium chloride, etc. In someembodiments, an aqueous liquid may comprise water, sodium chloride at aconcentration of about 100 mM to about 200 mM, potassium chloride at aconcentration of about 2 mM to about 3 mM, and phosphate buffer at aconcentration of about 5 mM to about 15 mM, wherein the pH of the liquidis about 7 to about 8.

A hydrogel may be used in a soft tissue aesthetic product. A soft tissueaesthetic product may comprise: an aesthetic device having a formsuitable for injecting or implanting into human tissue; and a labelcomprising instructions to inject or implant the aesthetic componentinto human tissue; wherein the aesthetic device comprises a crosslinkedmacromolecular matrix described herein. Some products may comprise thecrosslinked macromolecular matrix in hydrogel form.

Some embodiments include a method of improving an aesthetic quality ofan anatomic feature of a human being comprising: injecting or implantingan aesthetic device into a tissue of the human being to thereby improvethe aesthetic quality of the anatomic feature; wherein the aestheticdevice comprises a crosslinked macromolecular matrix comprisingdescribed herein. In some embodiments, the crosslinked macromolecularmatrix used in the product may be in hydrogel form.

In some embodiments, a hydrogel of a crosslinked macromolecular complexmay have a storage modulus of about 1 Pa to about 10,000 Pa, about 50 Pato 10,000 Pa, about 500 Pa to about 1000 Pa, about 556 Pa, about 560 Pa,about 850 Pa, about 852 Pa, or any value in a range bounded by, orbetween, any of these values.

In some embodiments, a hydrogel of a crosslinked macromolecular complexmay have a loss modulus of about 1 Pa to about 500 Pa, about 10 Pa to200 Pa, about 100 Pa to about 200 Pa, about 20 Pa, about 131 Pa, about152 Pa, or any value in a range bounded by, or between, any of thesevalues.

In some embodiments, a hydrogel of a crosslinked macromolecular complexmay have an average extrusion force of about 20 N to 30 N, or about 25N, when the hydrogel is forced through a 30G needle syringe by movingthe plunger of a 1 mL syringe containing the hydrogel at a rate of 100mm/min for about 11 mm, and measuring the average force from about 4 mmto about 10 mm.

A crosslinked macromolecular complex may have tunable swellingproperties based on reaction conditions and hydrogel dilution. In someembodiments, a crosslinked macromolecular complex may have a swellingratio of about 1 to about 7. A swelling ratio is the ratio of the weightof the crosslinked macromolecular complex when saturated with water tothe weight of the crosslinked macromolecular complex without any water.More specifically, the swelling ratio is the ratio of the mass of thegel which has been allowed to fully swell to the mass of the gel at itsinitial concentration.

In a crosslinking reaction, the molecular weight of a hyaluronic acidmay vary. In some embodiments, a hyaluronic acid may have a molecularweight of about 500,000 daltons to about 10,000,000 daltons, about1,000,000 daltons to about 5,000,000 daltons, or about 1,000,000 daltonsto about 3,000,000 daltons. When the crosslinking reaction occurs, theresulting crosslinked macromolecular product may have a hyaluronic acidcomponent derived from the hyaluronic acid in the crosslinking reaction.Thus, the ranges recited above may also apply to the molecular weight ofa hyaluronic acid component, e.g. about 500,000 daltons to about10,000,000 daltons, about 1,000,000 daltons to about 5,000,000 daltons,or about 1,000,000 daltons to about 3,000,000 daltons. The term“molecular weight” is applied in this situation to a portion of thematrix even though the hyaluronic acid component may not actually be aseparate molecule due to the crosslinking.

The concentration of hyaluronic acid in an aqueous pre-reaction solutionor a crosslinking reaction mixture may vary. In some embodiments,hyaluronic acid is present at about 3 mg/mL to about 100 mg/mL, about 6mg/mL to about 24 mg/mL, about 1 mg/mL to about 30 mg/mL, about 1.7mg/mL, about 3 mg/mL, about 6 mg/mL, about 12 mg/mL, about 16 mg/mL, orabout 24 mg/mL.

Any type of collagen may be used in the methods and compositionsdescribed herein. In some embodiments, collagen type I, collagen typeIII, collagen type IV, collagen type VI, or a combination thereof, maybe used. In some embodiments, a collagen or a collagen componentcomprises collagen type I or collagen type III. In some embodiments, thecollagen component comprises collagen type V.

A collagen may be derived from cell culture, animal tissue, orrecombinant means, and may be derived from human, porcine, or bovinesources. Some embodiments comprise collagen derived from humanfibroblast culture. Some embodiments comprise collagen that has beendenatured to gelatin. The source and/or collagen extraction/processingconditions can alter the way in which collagen macromolecules bundletogether to form supramolecular structures. These higher orderstructures can have effects on the gel physical properties (stiffness,viscosity) and may also have an effect on the reactivity of the collagento crosslinking reagents.

Collagen concentration in an aqueous pre-reaction solution or acrosslinking reaction mixture may vary. In some embodiments, collagenmay be present at a concentration of about 1 mg/mL to about 40 mg/mL,about 1 mg/mL to about 15 mg/mL, about 3 mg/mL to about 12 mg/mL, about1.7 mg/mL, about 3 mg/mL, about 6 mg/mL, about 8 mg/mL, or about 12mg/mL. The collagen concentration has an effect on the physicalproperties of the gel (stiffness, viscosity). In general, highercollagen concentrations lead to a higher elastic modulus.

In some embodiments, the weight ratio of hyaluronic acid to collagen ina aqueous pre-reaction solution or a aqueous pre-reaction solution or acrosslinking reaction mixture (e.g. [wt hyaluronic acid]/[wt collagen])may be about 0.5 to about 3, about 1 to about 3, about 1 to about 2,about 1, or about 2. When the crosslinking reaction occurs, theresulting crosslinked macromolecular product may have a collagencomponent derived from the collagen in the crosslinking reaction. Thus,the resulting crosslinked macromolecular matrix may have a weight ratioof hyaluronic acid component to collagen component that corresponds tothe weight ratio in the crosslinking reaction, e.g. about 0.5 to about3, about 1 to about 3, about 1 to about 2, about 1, or about 2.

In other embodiments of the invention, the compositions have an HA tocollagen ratio of between about 0.5 to 1 and about 7 to 1.

A salt may help to screen the negative charges of hyaluronic acid frompositive charges of collagen, and may thus prevent precipitation of apolyionic ion complex from solution. However, high concentrations ofsalt may reduce the solubility of some components in solution. Thus, insome embodiments, the salt concentration of an aqueous pre-reactionsolution or a crosslinking reaction mixture may be high enough to screenthe charges so that the polyionic ion complex is not formed, but alsolow enough so that the components of the mixture remain in solution. Forexample, the total salt concentration of some aqueous pre-reactionsolutions or crosslinking reaction mixtures may be about 10 mM to about1 M, for example, between about 5 mM to about 0.5 M, for example,between about 2 mM to about 0.2 M.

Some salts in an aqueous pre-reaction solution or a crosslinkingreaction mixture may be non-coordinating buffers. Any non-coordinatingbuffer may be used that is capable of buffering the mixture and does notcoordinate with metal atoms or ions in the collagen. In someembodiments, the buffer does not react with the crosslinking reagents(carbodiimide and additive). For example, acetate or phosphate buffersmay not be used in these embodiments. Examples of suitablenon-coordinating buffers may include, but are not limited to,2-(N-morpholino)ethanesulfonic acid (MES),3-(N-morpholino)propanesulfonic acid (MOPS),4-(2-hydroxyethyl)-1-piperazinyl) ethanesulfonic acid (HEPES),3-[4-(2-hydroxyethyl)-1-piperazinyl]propanesulfonic acid (HEPPS),N-cyclohexyl-2-aminoethanesulfonic acid (CHES),N-cyclohexyl-3-aminopropanesulfonic acid (CAPS), etc.

The concentration of a non-coordinating buffer may vary. For example,some aqueous pre-reaction solutions or crosslinking reaction mixturesmay have a buffer concentration in a range of about 10 mM to about 1 M,about 10 mM to about 500 mM, about 20 mM to about 100 mM, or about 25 mMto about 250 mM. Some aqueous pre-reaction solutions or crosslinkingreaction mixtures comprise MES at a concentration of about 20 mM toabout 200 mM, about 20 mM to about 100 mM, about 100 mM, or about 180mM.

Non-buffering salts may also be included in an aqueous pre-reactionsolution or a crosslinking reaction mixture as an alternative to, or inaddition, to buffering salts. Some examples may include sodium chloride,potassium chloride, potassium bromide, sodium bromide, lithium chloride,lithium bromide, sodium iodide, and potassium iodide. The concentrationof a non-buffering salt may vary. For example, some mixtures may have anon-buffering salt concentration in a range of about 10 mM to about 1mM, about 30 mM to about 500 mM, or about 50 mM to about 300 mM. In someembodiments, sodium chloride may be present at a concentration in arange of about 0.5% w/v to about 2% about 0.9% w/v, about 1.6% w/v,about 20 mM to about 1 mM, about 40 mM to about 500 mM, about 50 to 300mM, about 80 mM to about 330 mM, about 150 mM, or about 270 mM.

The pH of an aqueous pre-reaction solution may be lower than the pH of acrosslinking reaction mixture. If the salt content of the aqueouspre-reaction solution is low, the pH may be lower to enhance solubilityof the hyaluronic acid and the collagen. If the salt content is higher,the pH may be higher in the aqueous pre-reaction solution. In someembodiments, the pH of the aqueous pre-reaction mixture is about 1 toabout 8, about 3 to about 8, about 4 to about 6, about 4.7 to about 7.4,or about 5.4. For low salt concentrations, the pH may be about 1 toabout 4 or about 1 to about 3.

In some embodiments, pH may be adjusted to neutral to allow collagengelation or fiber formation before adding a coupling agent.

In some embodiments, the pH may be adjusted to neutral immediately priorto, around the time of, or after adding a coupling agent, such thatcollagen gelation is reduced or does not substantially occur.

Any water-soluble coupling agent may be used that can crosslinkhyaluronic acid to collagen. Some non-limiting examples of a couplingagent include carbodiimides such as N,N′-dicyclohexylcarbodiimide (DCC),N,N′-diisopropylcarbodiimide (DIC), or1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC). Carbodiimidecoupling agents may facilitate ester or amide bond formation withoutbecoming part of the linkage. However, other coupling agents that becomepart of the crosslinking group may be used. The concentration of acoupling agent may vary. In some embodiments, a coupling agent may bepresent at about 2 mM to about 150 mM, about 2 mM to about 50 mM, about20 mM to about 100 mM, or about 50 mM. In some embodiments, the couplingagent is EDC that is present at a concentration of about 20 mM to about100 mM, about 2 mM to about 50 mM, or about 50 mM.

As a result of a crosslinking reaction, a crosslinked macromolecularmatrix may comprise a crosslinking component that crosslinks orcovalently connects the hyaluronic acid component to the collagencomponent. A crosslink component comprises a plurality of crosslinkunits, or individual covalent bonding links, between the hyaluronic acidcomponent and the collagen component. At least a portion of thecrosslink units comprise an ester bond or an amide bond. In someembodiments, at least a portion of the crosslink units may be —CON— or—CO₂—, where the N is a nitrogen from an amino acid residue.

An activating agent may be used to increase the ratio of amide bondscompared to ester bonds formed in the crosslinked product. In someembodiments, an activating agent may be a triazole such ashydroxybenzotriazole (HOBT) or 1-hydroxy-7-azabenzotriazole (HOAT); afluorinated phenol such as pentafluorophenol; a succinimide such asN-hydroxysuccinimide (NHS) or N-hydroxysulfosuccinimide (sulfoNHS), andthe like.

The concentration of an activating agent may vary. In some embodiments,the activating agent may have a concentration of about 2 mM to about 200mM, about 2 mM to about 50 mM, about 20 mM to about 100 mM, or about 50mM. In some embodiments, the activating agent may be NHS or sulfoNHS isat a concentration of about 2 mM to about 50 mM. In some embodiments,the activating agent may be N-hydroxysulfosuccinimide, sodium salt, at aconcentration of about 20 mM to about 100 mM, or about 50 Mm.

In some embodiments, a crosslinking reaction mixture may comprise acarbodiimide coupling agent and an activating agent. In someembodiments, the coupling agent is EDC and the activating agent is NHSor sulfoNHS. In some embodiments EDC is present at a concentration ofabout 2 mM to about 50 mM and NHS or sulfoNHS is present at about 2 mMto about 50 mM.

In some embodiments, a crosslinking reaction mixture may comprisehyaluronic acid at a concentration of about 1.7 mg/mL, collagen at aconcentration of about 1.7 mg/mL, 2-(N-morpholino)ethanesulfonic acid ata concentration of about 100 mM, sodium chloride at a concentration ofabout 0.9 wt % or about 150 mM,1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at a concentration ofabout 50 mM, and N-hydroxysulfosuccinimide sodium salt at aconcentration of about 50 Mm, wherein the solution has a pH of about5.4.

In some embodiments, a crosslinking reaction mixture may comprisehyaluronic acid at a concentration of about 6 mg/mL, collagen at aconcentration of about 6 mg/mL, 2-(N-morpholino)ethanesulfonic acid at aconcentration of about 180 mM, sodium chloride at a concentration ofabout 1.6 wt % or about 270 mM,1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at a concentration ofabout 50 mM, and N-hydroxysulfosuccinimide sodium salt at aconcentration of about 50 mM, wherein the solution has a pH of about5.4.

In some embodiments, a crosslinking reaction mixture may comprisehyaluronic acid at a concentration of about 16 mg/mL of, collagen at aconcentration of about 8 mg/mL, 2-(N-morpholino)ethanesulfonic acid at aconcentration of about 100 mM, sodium chloride at a concentration ofabout 0.9 wt % or about 150 mM,1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at a concentration ofabout 50 mM, and N-hydroxysulfosuccinimide sodium salt at aconcentration of about 50 mM, wherein the solution has a pH of betweenabout 4.5 and 5.5, for example, about 5.2.

In some embodiments, a crosslinking reaction mixture may comprisehyaluronic acid at a concentration of about 12 mg/mL, collagen at aconcentration of about 12 mg/mL, 2-(N-morpholino)ethanesulfonic acid ata concentration of about 100 mM, sodium chloride at a concentration ofabout 0.9 wt % or about 150 mM,1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at a concentration ofabout 50 mM, and N-hydroxysulfosuccinimide sodium salt at aconcentration of about 50 mM.

In some embodiments, a crosslinking reaction mixture may comprisehyaluronic acid at a concentration of about 3 mg/mL, collagen at aconcentration of about 3 mg/mL, 2-(N-morpholino)ethanesulfonic acid at aconcentration of about 100 mM, sodium chloride at a concentration ofabout 0.9 wt % or about 150 mM,1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at a concentration ofabout 50 mM, and N-hydroxysulfosuccinimide sodium salt at aconcentration of about 50 mM, wherein the solution has a pH of about5.4.

In some embodiments, a crosslinking reaction mixture may comprisehyaluronic acid at a concentration of about 12 mg/mL, collagen at aconcentration of about 6 mg/mL, 2-(N-morpholino)ethanesulfonic acid at aconcentration of about 100 mM, sodium chloride at a concentration ofabout 0.9 wt % or about 150 mM,1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at a concentration ofabout 50 mM, and N-hydroxysulfosuccinimide sodium salt at aconcentration of about 50 mM, wherein the solution has a pH of about5.4.

In some embodiments, a crosslinking reaction mixture may comprisehyaluronic acid at a concentration of about 24 mg/mL, collagen at aconcentration of about 12 mg/mL, 2-(N-morpholino)ethanesulfonic acid ata concentration of about 100 mM, sodium chloride at a concentration ofabout 0.9 wt % or about 150 mM,1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at a concentration ofabout 50 mM, and N-hydroxysulfosuccinimide sodium salt at aconcentration of about 50 mM, wherein the solution has a pH of about5.4.

In some embodiments, a crosslinking reaction mixture may comprisehyaluronic acid at a concentration of about 1 mg/mL to about 20 mg/mL,collagen at a concentration of about 1 mg/mL to about 15 mg/mL,2-(N-morpholino)ethanesulfonic acid at a concentration of about 20 mM toabout 200 mM, sodium chloride at a concentration of about 0.5 wt % toabout 2 wt % or about 80 mM to about 330 mM,1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at a concentration ofabout 20 mM to about 100 mM, and N-hydroxysulfosuccinimide sodium saltat a concentration of about 20 mM to about 100 mM, wherein the solutionhas a pH of about 4 to about 6.

Example 1 Method of Making an Injectable Composition

Solutions of hyaluronic acid (HA) and collagen were produced bydissolving 15 mg of 2.0 MDa hyaluronic acid in 5 mL of humancollagen(III) solution at 3 mg/mL in 0.01 N hydrochloric acid(Fibrogen). The hyaluronic acid/collagen solution was then lyophilizedat −50° C. and 0.02 Torr. The resulting sponges were soaked in 20 mL ofethanol:water mixture at ratios varying from 1:2 to 5:1 with 50 mM of1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and 50 mM ofN-hydroxysulfosuccinimide sodium salt for 24 hrs. The crosslinked gelswere then washed in 70% isopropanol/30% water for sterilization followedby five washes in sterile phosphate buffer for purification.

Example 2 Method of Making an Injectable Composition

A solution of HA at 3.4 mg/mL was created by dissolving 34 mg of 2 MDaHA in 10 mL of 100 mM MES buffer with 0.9 wt % NaCl, pH 4.7. Upon fullhydration and dissolution of the HA, this solution was mixed with 10 mLof 3.4 mg/mL human collagen(III) solution in 100 mM HCl. The pH of theresulting HA/collagen(III) solution was adjusted to 5.4 with 10 mM NaOHsolution. EDC (192 mg) and 217 mg of sulfoNHS (50 mM each) were added tothe HA/collagen(III) solution and mixed thoroughly. The crosslinkingreaction proceeded for 18 hrs before the gel was particulated through a100 micron pore-sized mesh.

Example 3 Method of Making an Injectable Composition

Rat tail collagen(I) in 0.01 N hydrochloric acid (Invitrogen) wasconcentrated from 5 mg/mL to 8 mg/mL using a centrifugal filtrationdevice with 20 kDa molecular weight cutoff. HA (160 mg, 2 MDa) was addedto 10 mL of the collagen solution and allowed to hydrate for 60 minutes.The solution was then homogenized by passing from syringe to syringethrough a luer-luer connector. NaCl (93 mg) and 201 mg of MES were addedto the solution and mixed. EDC (98 mg) and 111 mg of sulfoNHS were addedto the solution and quickly mixed. Finally, 200 μL of 1 N NaOH was addedto the solution which was mixed by syringe-to-syringe passing. Thereaction solution was transferred to a glass vial and centrifuged for 5min at 4000 RPM to remove air bubbles. The gel was then particulatedthrough a 60 micron pore-sized mesh. Following sizing, the gel wassterilized by dialysis through a 20 kDa molecular-weight cut-offcellulose ester membrane against 70% isopropanol/30% water for 3 hrs at4° C. Dialysis was then continued against sterile phosphate buffer for48 hrs at 4° C. with three changes of buffer. The gel was then dispensedinto syringes under aseptic conditions.

Example 4 Method of Making an Injectable Composition

Rat tail collagen(I) in 0.01 N hydrochloric acid (Invitrogen) wasconcentrated from 5 mg/mL to 12 mg/mL using a centrifugal filtrationdevice with 20 kDa molecular weight cutoff. HA (120 mg, 2 MDa) was addedto 10 mL of the collagen solution and allowed to hydrate for 60 minutes.The solution was then homogenized by passing from syringe to syringethrough a luer-luer connector. NaCl (93 mg) and 201 mg of MES were addedto the solution and mixed. EDC (98 mg) and 111 mg of sulfoNHS were addedto the solution and quickly mixed. Finally, 200 μL of 1 N NaOH was addedto the solution which was mixed by syringe-to-syringe passing. Thereaction solution was transferred to a glass vial and centrifuged for 5min at 4000 RPM to remove air bubbles. The gel was then particulatedthrough a 60 micron pore-sized mesh. Following sizing, the gel wassterilized by dialysis through a 20 kDa molecular-weight cut-offcellulose ester membrane against 70% isopropanol/30% water for 3 hrs at4° C. Dialysis was then continued against sterile phosphate buffer for48 hrs at 4° C. with three changes of buffer. The gel was then dispensedinto syringes under aseptic conditions.

Example 5 Method of Making an Injectable Composition

Rat tail collagen(I) in 0.01 N hydrochloric acid (Invitrogen) wasconcentrated from 5 mg/mL to 12 mg/mL using a centrifugal filtrationdevice with 20 kDa molecular weight cutoff. HA (120 mg, 2 MDa) was addedto 10 mL of the collagen solution and allowed to hydrate for 60 minutes.The solution was then homogenized by passing from syringe to syringethrough a luer-luer connector. NaCl (93 mg), 201 mg of MES, and 200 μLof 1 N NaOH were added to the solution, mixed, and given 45 minutes forcollagen polymerization. EDC (98 mg) and 111 mg of sulfoNHS were thenadded and the final solution was mixed by syringe-to-syringe passing.The reaction solution was transferred to a glass vial and centrifugedfor 5 min at 4000 RPM to remove air bubbles. The gel was thenparticulated through a 60 micron pore-sized mesh. Following sizing, thegel was sterilized by dialysis through a 20 kDa molecular-weight cut-offcellulose ester membrane against 70% isopropanol/30% water for 3 hrs at4° C. Dialysis was then continued against sterile phosphate buffer for48 hrs at 4° C. with three changes of buffer. The gel was then dispensedinto syringes under aseptic conditions.

Example 6 Rheology Characterization of the Compositions

Oscillatory parallel plate rheology was used to characterize themechanical properties of gels using an Anton Paar MCR 301. A platediameter of 25 mm was used at a gap height of 1 mm. A frequency sweepfrom 0.1 to 10 Hz at a fixed strain of 2% with logarithmic increase infrequency was applied followed by a strain sweep between 0.1% and 300%at a fixed frequency of 5 Hz with logarithmic increase in strain. Thestorage modulus (G′) and loss modulus (G″) were determined fromfrequency sweep measurements at 5 Hz.

The gel from Example 4 had a storage modulus (G′) of 556 Pa and lossmodulus (G″) of 131 Pa. The frequency sweep (A) and strain sweep (B) areshown in FIG. 1.

Example 7 Extrusion Test

In order to determine the force required to extrude the gels, they wereejected from 1 mL BD syringes through 30G needles using an Instron 5564with Bluehill 2 software. The plunger was pushed at a rate of 100 mm/minfor 11.35 mm and the extrusion profile was recorded.

The extrusion profile through a 30G needle for gel from Example 4 isshown in FIG. 2. The gel had an average extrusion force of 25 N from 4through 10 mm.

Example 8 Method of Making Dermal Fillers

Hyaluronic acid, 2 MDa molecular weight, was dissolved in humancollagen(I) solution in 0.01 N hydrochloric acid (Advanced BioMatrix).Sodium chloride was added at 0.9 wt % and 2-(N-morpholino)ethanesulfonicacid was added at 100 mM to the solution and mixed. The hyaluronic acidwas allowed to hydrate for 1 hr and the solution was homogenized bysyringe-to-syringe mixing. The pH of the solution was adjusted to 5.4 byaddition of 1 N sodium hydroxide. 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (50 mM) and N-hydroxysulfosuccinimide sodium salt (50 mM)were added to the hyaluronic acid/collagen solution and quickly mixed bysyringe-to-syringe transfer. The solution was transferred to a glassvial and centrifuged for 5 min at 4000 RPM to remove air bubbles. Theresulting gel was allowed to react for 16 hrs at 4° C. The gel was thenparticulated through a 100 micron pore-sized mesh. Following sizing, thegel was sterilized by dialysis through a 20 kDa molecular-weight cut-offcellulose ester membrane against 70% isopropanol/30% water for 3 hrs at4° C. Dialysis was then continued against sterile phosphate buffer, pH7.4, for 48 hrs at 4° C. with four changes of buffer. The gel was thendispensed into syringes under aseptic conditions.

This procedure was used to produce hydrogels with varying concentrationsof hyaluronic acid and collagen. When required, human collagen(I) in0.01 N hydrochloric acid was concentrated from 3 mg/mL to the desiredreaction concentration in 20 kDa molecular-weight cut-off centrifugalfiltration devices. A 50 mL sample of each gel was synthesized,sterilized by exposure to 70% isopropanol, and purified by dialysisagainst phosphate buffer, pH 7.4. The gels synthesized are described inTable 2 along with their rheological properties.

TABLE 2 Hyaluronic acid-human collagen(I) hydrogel synthesisconcentrations and rheological properties Sample [HA] [Col(I)] G′ G″ ID(mg/mL) (mg/mL) (Pa) (Pa) A 3 3 199 24.6 B 12 6 1260 154 C 16 8 2450 288D 12 12 3160 420 E 24 12 5440 433 F 12 3 1110 52.2 G 16 3 1490 60.6 H 203 1770 49.5

Example 9 Biopolymer Concentration of the Dermal Fillers

In order to determine the biopolymer concentration in gels, the weightof the hydrated gel was compared to that of dried gel. A 2 mL sample ofgel was weighed and dried by flash-freezing in liquid nitrogen followedby lyophilization at −50° C. and 0.02 Torr. A solution of theappropriate buffer was also weighed and dried in the same fashion toaccount for salt content of the gel. The total solids content of the gelwas calculated by dividing the dry weight by the wet volume, assuming 1g/mL density for the wet gel, to give a value in mg/mL. The salt solidscontent was then subtracted from this value to determine the biopolymerconcentration in the gel.

TABLE 3 Final concentrations of hyaluronic acid-human collagen(I)hydrogels Final Sample [HA] [Col(I)] concentration ID (mg/mL) (mg/mL)(mg/mL) A 3 3 5.3 B 12 6 16.3 C 16 8 19.4 D 12 12 22.6 E 24 12 31.6

Example 10 Swelling Ratios

Swelling ratios relative to initial water content were determined forgels by increase in weight when equilibrated with phosphate buffer. Foreach gel, approximately 1 mL was injected into a 15 mL Falcon tube andweighed, followed by addition of 10 mL of phosphate buffered saline, pH7.4. The gels were thoroughly mixed with the buffer and vortexed for 30seconds. The gels were then allowed to equilibrate in the buffer for 48hrs at 4° C. After this time, the suspensions were centrifuged at 4000RPM in a swinging bucket rotor for 5 minutes. The supernatant buffer wasthen decanted and the weight of the swollen gel was measured. Theswelling ratio was determined by dividing the final weight of theswollen gel by the weight of the initial gel.

TABLE 4 Swelling ratios of hyaluronic acid-human collagen(I) hydrogelsSample [HA] [Col(I)] Swelling ID (mg/mL) (mg/mL) ratio A 3 3 0.96 B 12 61.67 C 16 8 1.69 D 12 12 1.49 E 24 12 1.65

Example 11 HA/Collagen for Facial Defects of Check

This example illustrates the use of compositions and methods disclosedherein for a facial disorder.

A 58-year-old woman presented with a lean face. She felt her face lookedold, sad and bitter because of the less fullness of her cheek contour.Pre-operative evaluation of the person includes routine history andphysical examination in addition to thorough informed consent disclosingall relevant risks and benefits of the procedure. The physicianevaluating the individual determines that she is a candidate foradministration of the dermal filler compositions and methods disclosedherein.

A composition of the invention, such as described in EXAMPLE 4, isprovided in a 20 mL syringe. One-holed blunt infiltration cannulas (3 mminner diameter) are used to place about 15 mL of the composition in thesyringe subcutaneously and under superficial musculoaponeurotic systeminto the left and right cheeks.

The individual is monitored for approximately 7 days. The physicianevaluates the treatment area and determines that the treatment wassuccessful. The woman's cheeks are fuller than prior to treatment. Boththe woman and her physician are satisfied with the results of theprocedure because she looks younger than she did when she came in fortreatment.

Example 12 Treatment of Facial Defects of Eyelids

This example illustrates the use of compositions and methods disclosedherein for a treatment of eyelid defects.

A 37-year-old woman presented with fine wrinkles around her eyes and shereports that her eyes made her look old and angry. Pre-operativeevaluation of the person includes routine history and physicalexamination in addition to thorough informed consent disclosing allrelevant risks and benefits of the procedure. The physician evaluatingthe individual determines that she is a candidate for administration ofthe dermal filler compositions and methods disclosed herein.

A composition, such as made as described in Example 5, is provided in a20 mL syringe. About 2.5 mL of the composition is injected with a fineneedle subcutaneously in the skin beneath the wrinkles into the regionsadjacent the eyes.

The individual is monitored for approximately 7 days. The physicianevaluates the eye of the patient and determines that the treatment wassuccessful. Both the woman and her physician are satisfied with theresults of the procedure because her eyes appear refreshed and the skinappears rejuvenated. Approximately one year after the procedure, thewoman indicates that her quality of life has improved.

Example 13 Treatment of Acne Scars

This example illustrates the use of compositions and methods disclosedherein for treatment of acne scars.

A 25-year-old man presents with moderate acne scarring on his jaw lineincluding depressions and pitting. He reports that he is dissatisfiedwith his appearance and feels he is socially inhibited due to hisperception of his appearance. Pre-operative evaluation of the personincludes routine history and physical examination in addition tothorough informed consent disclosing all relevant risks and benefits ofthe procedure. The physician evaluating the individual determines thathe is a candidate for administration of the dermal filler compositionsand methods disclosed herein.

A composition, such as that made as described in Example 12, is providedin 10 mL syringes. The physician injects a small amount of thecomposition below the skin in each depressed or pitted area of thepatient's jawline to raise the area to match the surrounding skin.

The individual returns for a follow up visit with the physician in 14days. The physician evaluates the patient and determines that thetreatment was successful. The man reports he is satisfied with theresults of the procedure because his skin is more smooth in appearanceand the acne scarring is substantially less visible. Approximately sixmonths after the procedure, the man returns for a follow up treatment.He reports to the physician that his quality of life has greatlyimproved since the procedure and he is no longer shy about hisappearance.

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties such as molecular weight, reaction conditions,and so forth used in the specification and claims are to be understoodas being modified in all instances by the term “about.” Accordingly,unless indicated to the contrary, the numerical parameters set forth inthe specification and attached claims are approximations that may varydepending upon the desired properties sought to be obtained. At the veryleast, and not as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical parameter shouldat least be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques.

The terms “a,” “an,” “the,” and similar referents used in the context ofdescribing the invention (especially in the context of the followingclaims) are to be construed to cover both the singular and the plural,unless otherwise indicated herein or clearly contradicted by context.All methods described herein can be performed in any suitable orderunless otherwise indicated herein or otherwise clearly contradicted bycontext. The use of any and all examples, or exemplary language (e.g.,“such as”) provided herein is intended merely to better illuminate theinvention and does not pose a limitation on the scope of any claim. Nolanguage in the specification should be construed as indicating anynon-claimed element essential to the practice of the invention.

Groupings of alternative elements or embodiments disclosed herein arenot to be construed as limitations. Each group member may be referred toand claimed individually or in any combination with other members of thegroup or other elements found herein. It is anticipated that one or moremembers of a group may be included in, or deleted from, a group forreasons of convenience and/or patentability. When any such inclusion ordeletion occurs, the specification is deemed to contain the group asmodified thus fulfilling the written description of all Markush groupsused in the appended claims.

Certain embodiments are described herein, including the best mode knownto the inventors for carrying out the invention. Of course, variationson these described embodiments will become apparent to those of ordinaryskill in the art upon reading the foregoing description. The inventorexpects skilled artisans to employ such variations as appropriate, andthe inventors intend for the invention to be practiced otherwise thanspecifically described herein. Accordingly, the claims include allmodifications and equivalents of the subject matter recited in theclaims as permitted by applicable law. Moreover, any combination of theabove-described elements in all possible variations thereof iscontemplated unless otherwise indicated herein or otherwise clearlycontradicted by context.

In closing, it is to be understood that the embodiments disclosed hereinare illustrative of the principles of the claims. Other modificationsthat may be employed are within the scope of the claims. Thus, by way ofexample, but not of limitation, alternative embodiments may be utilizedin accordance with the teachings herein. Accordingly, the claims are notlimited to embodiments precisely as shown and described.

1. A method of improving an aesthetic quality of a soft tissue of ahuman subject, the method comprising: (a) providing adipose tissue; (b)providing a hydrogel composition comprising: (i) water; and (ii) ahyaluronic acid crosslinked with a collagen via a plurality of crosslinkunits, wherein at least a portion of the crosslink units comprise anamide bond; and wherein the hyaluronic acid concentration is from 6mg/mL to 20 mg/mL; the collagen concentration is from 3 mg/mL to 12mg/mL; the hyaluronic acid:collagen weight ratio is from 1:1 to 7:1; andthe hydrogel has a storage modulus value of between 850 Pa and 5,000 Pa;(c) contacting the hydrogel composition with the adipose tissue ex vivoto provide a mixture; and (d) administering the mixture to the softtissue of the subject; thereby improving the aesthetic quality of thesoft tissue. 2.-4. (canceled)
 5. The method of claim 1, wherein thecollagen is collagen type I, collagen type III, or a combinationthereof.
 6. The method of claim 1, wherein the collagen is collagen typeI.
 7. The method of claim 5 or 6, wherein the collagen is derived from ahuman or porcine source.
 8. The method of claim 1, wherein thehyaluronic acid has a molecular weight of about 1,000,000 Da to about5,000,000 Da.
 9. The method of claim 1, wherein the hyaluronic acid hasa molecular weight of about 1,000,000 Da to about 3,000,000 Da.
 10. Themethod of claim 1, wherein the ratio of the hyaluronic acid to thecollagen is 1:1 to 2:1.
 11. The method of claim 1, wherein the ratio ofthe hyaluronic acid to the collagen is 1:1.
 12. The method of claim 1,wherein the hydrogel has a storage modulus value of between 1,000 Pa and5,000 Pa.
 13. The method of claim 1, wherein the hydrogel has ahyaluronic acid concentration of 12 mg/mL or 16 mg/mL.
 14. The method ofclaim 1, wherein the hydrogel has a collagen concentration of 6 mg/mL, 8mg/mL or 12 mg/mL.
 15. The method of claim 1, wherein the hydrogel has ahyaluronic acid concentration of 12 mg/mL and a collagen concentrationof 6 mg/mL.
 16. The method of claim 1, wherein the hydrogel has ahyaluronic acid concentration of 12 mg/mL and a collagen concentrationof 12 mg/m L.
 17. The method of claim 1, wherein the hydrogel has ahyaluronic acid concentration of 16 mg/mL and a collagen concentrationof 8 mg/m L.
 18. The method of claim 1, wherein the administration isintradermal.
 19. The method of claim 1, wherein the administration issubcutaneous.
 20. The method of claim 1, wherein the administration isby injection.
 21. A method of improving an aesthetic quality of a softtissue of a human subject, the method comprising: (a) administering ahydrogel composition to the soft tissue of the subject, wherein thehydrogel composition comprises: (i) water; and (ii) a hyaluronic acidcrosslinked with a collagen via a plurality of crosslink units, whereinat least a portion of the crosslink units comprise an amide bond; andwherein the hyaluronic acid concentration is from 6 mg/mL to 20 mg/mL;the collagen concentration is from 3 mg/mL to 12 mg/mL; the hyaluronicacid:collagen weight ratio is from 1:1 to 7:1; and the hydrogel has astorage modulus value of between 850 Pa and 5,000 Pa; and (b) contactingthe hydrogel composition with adipose tissue in vivo; thereby improvingthe aesthetic quality of the soft tissue.
 22. The method of claim 21,wherein the collagen is collagen type I, collagen type III, or acombination thereof.
 23. The method of claim 21, wherein the collagen iscollagen type I.
 24. The method of claim 22 or 23, wherein the collagenis derived from a human or porcine source.
 25. The method of claim 21,wherein the hyaluronic acid has a molecular weight of about 1,000,000 Dato about 5,000,000 Da.
 26. The method of claim 21, wherein thehyaluronic acid has a molecular weight of about 1,000,000 Da to about3,000,000 Da.
 27. The method of claim 21, wherein the ratio of thehyaluronic acid to the collagen is 1:1 to 2:1.
 28. The method of claim21, wherein the ratio of the hyaluronic acid to the collagen is 1:1. 29.The method of claim 21, wherein the hydrogel has a storage modulus valueof between 1,000 Pa and 5,000 Pa.
 30. The method of claim 21, whereinthe hydrogel has a hyaluronic acid concentration of 12 mg/mL or 16mg/mL.
 31. The method of claim 21, wherein the hydrogel has a collagenconcentration of 6 mg/mL, 8 mg/mL or 12 mg/mL.
 32. The method of claim21, wherein the hydrogel has a hyaluronic acid concentration of 12 mg/mLand a collagen concentration of 6 mg/mL.
 33. The method of claim 21,wherein the hydrogel has a hyaluronic acid concentration of 12 mg/mL anda collagen concentration of 12 mg/mL.
 34. The method of claim 21,wherein the hydrogel hyaluronic acid has a concentration of 16 mg/mL anda collagen concentration of 8 mg/mL.
 35. The method of claim 21, whereinthe administration is intradermal.
 36. The method of claim 21, whereinthe administration is subcutaneous.
 37. The method of claim 21, whereinthe administration is by injection.